Experimental Study on Sand/Bed Collision Over the Gobi Surface

Abstract

The Gobi Desert is a vast semidesert area in China, which is mostly covered by gravel with minor vegetation. The Gobi in northern and northwestern part of China is believed to be the main source of sandstorms in East Asia (Sun et al., 2001), and the amount of dust released from the Gobi area (3.7 tons per day) during sandstorm is much higher than that from the sand desert area (0.8 tons per day; S. Chen et al., 2017). Dust emissions due to frequent sandstorms in the Gobi area (Jugder et al., 2012;Natsagdorj et al., 2003) usually accompanied by strong sand surface wind-blown sand movement, which causes great harm to various facilities and railway lines in the vicinity.The wind-blown sand is a typical two-phase (gas-solid) flow. It forms by the interaction between air and solid particulates (Z. Wang et al., 2009;Wu, 2003). Bagnold (1935) first combined theoretical studies on fluid mechanics with his long-time field investigations in the Libyan Desert and further with a series of wind tunnel experiments (Bagnold, 1941) to understand wind-blown sand. Since then, numerous studies have been carried out on the theoretical simulations and quantitative analysis of wind-blown sand (

Effects of Covering Layer of Sand Particles on Particle‐Bed Collision and Aeolian Sand Transport

“…In this study, the main instruments used for the collision process included a natural particle emitter (Y. Chen et al., 2019; Zhang, Huang, & Dun, 2022); and an image acquisition system (PowerView HS‐2000 high‐speed camera), as shown in Figure 2c. Compared with acoustic sensor measurements, photoelectric measurements have better accuracy and stability (Shen et al., 2004) and have been successfully used in collision experimental studies (Y. Chen et al., 2019).…”

Scaling laws for liftoff velocity for wind-transported particles during particle-bed collisions

“…The coefficient of restitution, CoR = v r / v i , represents the proportion of the momentum of the saltating particle that is retained when it rebounds (Zhang et al, 2022). CoR decreased linearly with increasing N s (Fig.…”

“…Because the collision occurs inside the near-surface boundary layer, the effect of air flow during a collision is negligible (Haff & Anderson, 1988, 1991. Many scholars have obtained splash functions by conducting particle-bed collision experiments without wind by using devices to launch the particles (Rioual et al, 2000(Rioual et al, , 2003Beladjine et al, 2007;Chen et al, 2019;Zhang et al, 2022). The most typical launch devices are launch guns and centrifugal launchers.…”

“…Because the splash functions are very sensitive to the density and Young's modulus (deformability) of the material, launch gun experiments cannot reflect the characteristics of natural sand transport well. Although centrifugal launchers can launch natural sand particles without generating a disruptive airflow, it is difficult to achieve an impact angle below 20°, which is much greater than the actual angle during natural sand transport (Chen et al, 2019;Zhang et al, 2022). Because splash functions are very sensitive to the impact angle, the resulting data don't reflect natural impact processes.…”

Turbulent Flow Structures Over a Gobi Surface and Their Impact on Aeolian Sand Transport

“…Gobi is a type of desert pavement widely distributed in Northwest China and Mongolia, and recent studies have shown that aeolian saltation over gobi differs from that over sand surfaces in the formation of a thicker saltation layer (e.g., Qu et al., 2023; Tan et al., 2020; Wang et al., 2022; Zhang et al., 2021) with nonmonotonic kinetic energy profiles (e.g., Tan et al., 2021) due to the difference in grain–bed collision processes (e.g., Tan et al., 2022; C. Zhang et al., 2022). These special characteristics make studies on aeolian sand transport over gobi very important in the field of aeolian research.…”